[GHC] #10727: compiler/rename/RnSource.lhs:429:14-81: Irrefutable pattern failed

[GHC]

#10727: compiler/rename/RnSource.lhs:429:14-81: Irrefutable pattern failed
-------------------------------------+-------------------------------------
              Reporter:  doelie      |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Compiler    |           Version:  7.4.1
              Keywords:              |  Operating System:  Linux
          Architecture:              |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
             Test Case:              |        Blocked By:
              Blocking:              |   Related Tickets:
Differential Revisions:              |
-------------------------------------+-------------------------------------
 see bug.sh in:
 http://zwizwa.be/stuff/ghc_bug.tgz


 make: Entering directory `/home/tom/pub/darcs/meta/siso'
 ghc Test.hs
 [ 9 of 10] Compiling Code             ( Code.hs, Code.o )
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.4.1 for x86_64-unknown-linux):
         compiler/rename/RnSource.lhs:429:14-81: Irrefutable pattern failed
 for pattern Data.Maybe.Just (inst_tyvars,
                                                         _,
                                                         SrcLoc.L _ cls,
                                                         _)


 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10727>
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